AITAH for telling my date that she's too old, 10 minutes in

Basically I have set up a coffee date via a friend. We met up, walked around for a few minutes, ordered a coffee and started to talk.

Around 10 minutes I asked how old she was and she ( with a lot of hesitation ) told me that she's 29, which I found alarming. It's your age, why do you need to think about it for 5 seconds? I told her I'm 24 and thought she looked considerably younger despite her age but followed up saying that " I'm looking for somebody in the range of 18-23 " to be younger than me because I'm looking for a long term partner that is fertile and is potentially able to bring multiple children to term without complications ( preferably ). She got up and left without saying anything, looking extremely upset. I let it be. There was nothing else I could do at that point.

Is there a more delicate way to say the same thing while keeping the honesty part intact without hurting her feelings or is that inevitable?